Hammer operated by compressed fluid.



0. E. SHAW.

HAMMER OPEBATBD BY'OUMPBESSBD FLUID. nrmounox rms un. no. ma.

1,061,203. Patented May 6, 1913.

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W/TNE88E8: INVENTOH um WWII N.. Alllmn II- l.

lconstantl CHARLES H. SHAW, OF -DENVER,ICOLORADO.

` HAMMER OPERATED BY COMPRESSED FLUID.

Spoottloation of Letton Patent.

Patented May (i, 19.13.

Application filed March 20, 1912. Serial No. 684,926.

l'o all whom, it may concern Be it known that I, CHAnLEs H. SHAW, a citizen of the United States, residin at Denver, in the county of Denver and tate of Colorado, have invented certain new and useful Improvements in Hammers Operated b Compressed Fluid; and I do hereby dec are the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it vxppertains to make and use the same.

ns invention relates to improvements in hammers and especially that class of hammers ordinarily operated by compressed air and ordinarily called air hammers or pneumatic hammers An object of my invention is to rovide, in a mechanism of the class descri ed, for economy in the quantit of air or other compressed fluid used an to make the piston strike a maximum hlow with the expenditure pf a minimum quantity of the compressed uid.

Another object of m invention is to rovide a mechanism o the class described with a minimum number of movable parts.

Another object of my invention is to rovide a hammer of the class describe .in which the com ressed fluid which o erates the piston shall) remain at substantia ly the same pressure against the rear of the iston during both the forwar and backwar movements of the piston, so long as compressed fluid is being supplied to the machine.

Another object of my invention is to provide, in a hammer of the class described, improved means for returning and forcing )ack the piston a ainst a constant pressure upon the rear en thereof.

Another object of m invention is to rovide, in a hammer of tl'ie class describe an arran ement of passages, valves and ports where y, from a single supply of compressed fluid to the mechanism, tie said compressed fluid will exerta constant and Substantially equal pressure upon the rear end of the piston at all times', during both forward and backward strokes, but whereby, also, the said compressed fluid will be sup lied automatically and intermittently to-t e front of the piston and against the same so that the piston will be alternately forced back against the constant pressure against its rear end and then released so that the said constant:

ressure will force it forward to strike the low.

With these and other objects in View my i invention comprises certain novel constructions, combinations and arrangements of parte as will be hereinafter fully described and claimed.

In the accompanying drawings, Figure l. represents a longitudinal view of my hammer showing the casing and other stationary parts in section und the piston und other moving parts in elevation and showing some of the ports and passages and showing the piston at the forward end of the stroke.

ig. 2 represents another longitudinal view of my hammer showing the casing and other stationary parts in section and showing thc piston and other moving parts in elevation and showing other ports and passages and showingbthe piston a roximately midway on the ack stroke. ig. 3 represents the` `central portion of my hammer showin the piston and associated grooves and exiaust passages in elevation as if the casing were transparent and showing the position of all passa es in the broken ends of the casing and s owing the piston on the back stroke after exhaustion of the air in front of the piston and while the back stroke is being completed by momentum of the piston. Fig. 4 represents a cross-section of the valve block of my hammer 'on line 1 2 of Fig. 1.

Like characters of reference represent corresponding parts throughout the several views.

The end of the hammer having the valve block will be referred to as the rear cnd and the movement of the iston toward the valve block will be referredj to as the hack stroke.

In the construction of my hammer l provide a casing F with a chuck O at its forward end in which chuck I provide a tappet block H, the chuck bein so constructed as to admit the end of a dril D or other tool. lt. is preferable to construct. the chuck and tuppet block as shown but this is no part of my present invention as any suitable moans for .closing the forward cud of the chamber li" while at the same tim'o communicating the blow from the piston within the chamber to the tool to be o erated, may be used.

The rear en( of the casing F is provided with a valve block B to which is attacla-.d a cap C. 'lhe connections of the casing with the chuck (A) aud valvel block Il and ol' tho ilO fil)

valve block B with the cap C are all air tight except where ports or'passages are indicated.

The casing F is constructed with a central chamber, having rear portion Fx which is, in diameter, the largest portion. The lor tion of the chamber next adjoining I*1 is designated as 'F2 and F and has the. smallest the chamber is widened into F. The casing F is also provided with annular grooves g, g and g2 'and with a plurality ofexhaust passages, e, communicating at theirinner ends with the annular grooves'g and 'g1 and at their outer ends with the atmosphere. Thecasing F is also provided with aI 'lurality of passagcs'b lcomtiiunicating"at t eir forward ends with chamber F andat their rear ends 'with 'annular rrooves b1 in the valve block. The casing is also provided with passage t communicating at its forward end with annular groove g? and at its rear end with annular gr'oove'tfl in the valve block.

The passages t and'b have been mentioned as vbeing formed inthe Casin'l lFbiit corresponding passages designate by tliesame letters are Lformed in the 'valve block B` 'connected with the passages in thecasing'F and thus form continuous 'passages 'connected 'with 'the chambers and'gro'ovesas 'above described. h

The 'piston P 'has its'orward end"'n lar: ed as at Pan'd "its "rea'end4 is smaller in i'a'me't'er`as at P2. The ceritral"`po'rtion of the piston'iscut a'wa *aseleti'rly shown at'P in 'Fig'. 1 'sbthatpw en 'the'pitn 'is in the "pos'iti'on' 'shown inFi'gfQya connection is.l formed between the anntilar igroo'vesj'y'. and g2 andvvh'en thepistbifis'at or near the enalof ai@ bnc'k'scroiss-inFigrniie annular 'grooves y" and '.l/ z aref'still connected. The extreme forward end of Ytliefpi'itn inay'bebeveled' as'at Pa in'ol'der tope'rmit; connection between chamberl*""and annular groove xf/ and the exhaust of the"cm pressed lfluid from Chamber F tthrough groove f/ and exhausts @,at anearli'ersta e of the back stroke than would be possibile were the forward end of thc-piston not so beveled.

'lhe valve block ll is constructed with an outer easing ll and Ian 'inner casing B.

There is an annular groove S in'the outer easing which grooveconnectswitli thestipi'ly passages S". lhis casing is also provi ed with a passage B" as slio'wnin Fig. l which connects with "the iitinosph'erethrough annular groove C* and passage. C'l le'ading'therefrom.

The vulve V is slidingly mounted within the inner casing B and iscoiis'tt'ilcted with tlielfo'rward end 'tliereof,`desi` natd'las V, smaller than the rear lend it. el'eof, desi uiitedfas V. p irtion,'V,of'-tihe valve 4is cnt away so as to fo'm dnnectin between iametcr and from this point forward lthe annular groove S4 and the ports b2 when the valve is in the forward position as shown in Fig. 1 and soas to form connection between the ports b2 and the annular groove ari'dport'B when the valve is in the position shown in Fig. 2. v

in order to describe the operation of the hammer I commence when the piston is at or near the extreme back stroke as in Fig.

3 at which time the valve V is also at the 75 extreme back stroke as in Fig. 2. Through 'the `passage lS I allow fluid under pressure to 'pass into the -mechanism through pas- Sages S* and S2 thus'fi'llinfy lthe 'chamber 'F1 with the fluid under fu'll pressure. This lldrives the piston 'forward until Athe rear of the piston passes "into annular groove g2 as clearly shown in Fig. 1, thus opening passage t for the assage of the compressed fluid from cham er Fl through F". into an- 'sa nular groove g and 'thence through 'passage t into annular groove `t,'th`ence throu h "port tz into lthe chamber t at ythe rear of 't e valve. The rear of the valve being larger than the forward end'and li'aving'a larger surface exposed to 'the pressure and *the pressure at'bth ends of the valvebcing the same perziinit'arem the valve will be moved vfofrwardfto the position shown in Fig. 1.

When the valve moves 'into the position in lFig. i, communication is opened between cannular groove'S and po'rts Y'so ithat the compressed fluid passes. from passagesS2 li'ltoaiinii'la'r grooves S, thence into ports b,"*th"rou 'h' thepassages 'b and thencento '100 the 'cham er"F"1n"fr`ont of'th'e head ofthe "Eistbnl'ltlius establishing 'pressure "at the cad o'f 'the fpist'onequal pr unit area to 'the 'pressi're at *hef rear of -t-he piston.

'Wli'ileitis true that the pressure is es- 105' y"-tflblish'ed 'in chamber 'Ff almost instan- 'tilncloiisly lup'on the opening of Ianrttilni' igroovelrf, as"abo`ve described. still it is 'n'ot lestablished qnickly'fenough to lprevent,

the momentum of the piston aided -the "110 constant pressnreat-itsrean from carrying the piston `to the com lotion `of the stroke :with 4full Iforce. At t ie'end of th(l 'stroke the piston very slightly rebounds 'from lthitappct block. bythe 'force of tlie blow, thusI `1 lf3 leaving the Ientire surface ot the 'forward end of the pistonex oscd to the pressure of the fluid fin cham -r li" and this pres- :aire lbeing eq'ual pert'iriit area to the vpressure at the rear of the iston and the snr 120 face of 4'the forward en( being larger than the 4surface ofthe rear lol" 4the piston, the piston "is forced back by the pressure in 4chamber vlt", against the 'pressure of the 'fluid in chamber 'l 'When '-tlie' iistonhas 121' Athusbeen' tforced back'tothe position shown in Fig. '2, communication 'is :established between 'c'hamb'er u and the atmosphere tltrongh 'tfhe 'passa e t 'annular'groove o, 'trut awayportion' of the piston, the anlflt Ii (l nular grooves g and g1 and thence through exhausts e. Through this channel the compressed fluid at the rear of the valve is exiausted and the pressure in chamber' F immedately forces the valve back to the position shown in Fig. 2 thus cutting off the communication from passages S2, through annular groove S* and orts b and passages b, with chamber Ii. The sup lv of compressed fluid is therefore cut o rom chamber F* when the piston reaches the position shown in Fig. 2. It will be noted that from this point the piston will be carried back by the pressure nlread established in chamber F as well as by its own momentum until it reaches the position shown in Fig; 3, when the pressure in chamber F will exhaust through groove g and exhausts c. It is clear that the iston will then continue on the back stroiie only so long as its momentum exceeds the pressure in chamber F. The momentum is overcome by this pressure when the enlarged portion Pl reaches a point in front of FB of the chamber, where the diameter of the chamber'decreases, which point is determined by the relation between the wei ht of the piston, the relative sizes of its orward and rear ends and the pressure under which the fluid is used. The piston then stops and is instantaneousl again forced forward as first above descri ed.

In lorder to eliminate the back ressure which would result, in chamber from the forward movement of the piston after it has assed annular groove g, annular roove is provided in the inner casing B of the valve block and communieating with the atmosphere through passa4 e Ba annular groove C1 and passage C. W ien the valve is in the position shown in Fig. 2 communication is established between chamber F and the atmosphere through assages b, ports b2 cut-away valve, annular groove li, passa e 13 and groove and passage Cl and C. Therefore. while the piston is passing forward, the fiuid in chamber I4" is forced out through the communication established, as above described, to the atmosphere and back pressure is avoided.

. It is preferable to have chamber F considerably larger than the portion of the piston which projects into it on the back stroke. 'Ihc reason for this is that the lar er the hulk of compressed fluid in cham r Fl portion V o the as compared to the bulk of that portion of the piston, the less will t-he pressure be increased or diminished by the piston being injected into or withdrawn from the chamber and the nearer constant and equal will the pressure remain in the chamber.

I claim- 1. In a device of the class described, a cylinder, a piston hammer mounted to reciprocatefreely in the cylinder and being of lar er area at its forward than its rearward en the said cylinder being provided with an inlet port and conduits leading from the inlet port to the front end of the cylinder and to an annular groove intermediate the ends of the cylinder, means to subject both ends of the piston to fluid pressure, and a valve mounted in the inlet port adapted at times to relieve the fluid pressure at the forward end of the piston.

2. In a device of the class dcscribed,' a cylinder, a piston hammer mounted to re.- ciprocate freely in the cylinder and provided with its forward end havin a greater aiea than its rearward end, sai cy inder being rovided with an inlet port and conduits eading from the inlet port to the forward end of the cylinder and to an annular groove intermediate the ends of the cylinder, means to introduce fluid under pressure through the inlet port and through the passa es to subject both ends of the piston to flui pressure, a valve introduced into the inlet port adapted to control the conduits and adapted at times to cut off communication etween the conduits and the inlet port and to open communication between the conduits and an exhaust.

3. In a device of the class described, a piston having its front end of larger transverse area than its rear end, a chamber at the rear thereof, means for supplying compressed fiuid to said chamber, a c iamber at the front of said piston, passages to said front chamber, an automatically operated valve, having its front end of a smaller transverse area than its rear end, for per mitting compressed fluid to pass intermittently from said means of supply, through said passages and into said front chamber.

In testimon whereof I afiix my signature in presence o two witnesses.

CHARLES H. SHAW.

Witnesses:

CAaLn Wlii'rniiicAD, A. FRANK Jamas.

pm of this patent may be obtained for five im each, by addrduing the Commissioner o! rannte. Washington, D. 0." 

